Surface functionalization with phosphazenes: Part 6. Modification of polyethylene-Co-polyvinylalcohol copolymer surface plates with fluorinated alcohols and azobenzene derivatives using chlorinated phosphazenes as coupling agents

In this paper we describe a two-step surface modification process of poly(ethylene-co-vinyl alcohol) by exploiting hexachlorocyclophosphazene and poly(dichlorophosphazene) as coupling agents. Part of the P-Cl groups of the chlorophosphazenes is first reacted with the surface hydroxylic groups of the substrate to form covalent P-O-C bonds, the remaining being utilized for successive substitution reactions with different nucleophiles (i.e. 2,2,2-trifluoroethanol, heptadecafluorononanol and 4-hydroxyazobenzene). Modified surface properties, such as hydrophobicity improvement with fluorinated alcohols and photochromic features with the azobenzene derivative, were verified by contact angle measurements and UV-Vis spectroscopy, respectively, while changes in surface composition were demonstrated through XPS spectroscopy.